docs: def file_url_to_local_path(file_url):
      """
      Parse a ``AutoConfigURL`` value with ``file://`` scheme into a usable local filesystem path.
  
      :param file_url: Must start with ``file://``.
      :return: A local filesystem path. It might not exist.
      """
      parts = urlparse(file_url)
      path = unquote(parts.path)
      if path.startswith('/') and not path.startswith('//'):
          if ON_DARWIN:
              return path
          if len(parts.netloc) == 2 and parts.netloc[1] == ':':  # Drive letter and colon.
              return parts.netloc + path
          return 'C:' + path  # Assume C drive if it's just a path starting with /.
      if len(path) > 2 and path[1] == ':':
          return path